FIG. 1 illustrates an exemplarily flow diagram of a typical design process 100 for ICs in accordance with the prior art. The process can be generally divided into a front end design phase and a back end development phase. During the front end phase, an engineer designs and develops a logical representation of an integrated circuit (IC) from a set of specifications in form of a schematic (stage 102). At a stage 104, the schematic is then loaded into a computer from which a circuit netlist is generated. The netlist defines the entire IC design including all components and interconnections.
Moreover, the IC information may be developed using hardware description language (HDL) and synthesis. With the aid of circuit simulation tools available on computers, a designer can then simulate the functionality of a given circuit at a stage 106. The circuit simulation process may involve several iterations of design modifications and improvements, until the circuit design is finalized at a stage 108.
The back end development involves several stages during which a final circuit layout (physical description) is developed based on the schematic design of the front end. In a stage 110, various building blocks (or cells), as defined by the finalized circuit schematic, are placed within a predefined floor plan. For ICs designed based on array or standard cell technology, the various building circuit blocks are typically predefined and made available in a cell library. For example, during the stage 110, a plurality of cells are selected from one or more cell libraries and the cell interconnects are determined. More particularly, groups of cells may be interconnected to function as a flip-flop, shift registers, and the like. The routing of wires to interconnect the cells and achieve the aforementioned goals is preformed during a routing stage 112, typically referred to as conducting paths, wires or nets. Accordingly, in the stage 112, interconnects between circuit elements are routed throughout the layout. In a stage 114, the accuracy of the layout is verified against the schematic and if no errors or design rule violations are found at a stage 116, the circuit layout information is used for the process of fabrication in a stage 118.
As discussed with respect to FIG. 1, a typical IC design can involve a number of complicated steps. For example, defection and tracking are extremely important to the success of the process 100 of FIG. 1. As the number of modules within each IC design increases, for example, to provide additional functionality required by today's demands, tracking defects becomes an ever-increasingly important part of the IC design process. Also, as the number of defects increases in the more complicated designs, ensuring that a defect is tracked properly becomes even more essential.